The present invention relates generally to operations performed in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides a method and apparatus for downhole retrieval of data, monitoring and tool actuation.
It is usually the case that a tubular string, is installed in a subterranean well with one or more items of equipment interconnected in the tubular string. Thereafter, a tool conveyed into the tubular string may be positioned relative to the item of equipment, engaged with the item of equipment and/or utilized to actuate the item of equipment, etc.
In the past, various mechanisms and methods have been utilized for positioning a tool relative to an item of equipment in a tubular string, for engaging the tool with the item of equipment and for utilizing the tool to actuate the item of equipment. For example, where the item of equipment is a sliding sleeve-type valve, a shifting tool is typically conveyed on wireline, slickline or coiled tubing into the valve and engaged with the sliding sleeve. An operator is aware that the shifting tool is properly positioned relative to the valve due to the engagement therebetween, as confirmed by the application of force to the shifting tool. The shifting tool may be configured so that it operatively engages only the desired sliding sleeve, out of multiple items of equipment installed in the tubular string, by equipping the shifting tool with a particular set of keys or lugs designed to engage only a particular profile formed in the desired sliding sleeve.
Unfortunately, it is often the case that the operator is not able to positively determine whether the shifting tool is properly engaged with the desired sliding sleeve, such as when the well is highly deviated. Additionally, the operator may not accurately know information which would aid in performance of the task of shifting the sleeve. For example, the operator might not know that an excessive pressure differential exists across the sleeve, or the operator might attempt to shift the sleeve to its fully open position not knowing that this should not be done with an excessive pressure differential across the sleeve. Thus, it may be clearly seen that improved methods of positioning, engaging and actuating tools are needed.
Many operations in wells would be enhanced if communication were permitted between an item of equipment installed in a tubular string and a tool conveyed into the string. For example, if a valve was able to communicate its identity to a shifting tool, an accurate determination could be made as to whether the tool should be engaged with the valve. If a valve was able to communicate to the tool data indicative of pressure applied to a closure member of the valve, such as a sliding sleeve, a determination could be made as to whether the tool should displace the closure member, or to what position the closure member should be displaced.
Improved communication methods would also permit monitoring of items of equipment in a well. In one application, a tool conveyed into a tubular string could collect data relating to the status of various items of equipment installed in the tubular string. It would be desirable, for example, to be able to monitor the status of a packer seal element in order to determine its remaining useful service life, or to be able to monitor the strain, pressure, etc. applied to a portion of the tubular string, etc.
Therefore, from the foregoing, it may be seen that it would be highly advantageous to provide improved methods and apparatus for downhole data retrieval, monitoring and tool actuation.
In carrying out the principles of the present invention, in accordance with an embodiment thereof, a system for facilitating downhole communication between an item of equipment installed in a tubular string and a tool conveyed into the tubular string is provided. Associated methods of facilitating such downhole communication are also provided, as well as applications in which the downhole communication is utilized for data retrieval, monitoring and tool actuation.
In one aspect of the present invention, the downhole communication system includes a first communication device associated with the item of equipment and a second communication device included in the tool. Communication may be established between the devices when the device in the tool is brought into sufficiently close proximity to the device associated with the item of equipment.
In another aspect of the present invention, the tool supplies power to the first device. Such provision of power by the tool may enable the first device to communicate with the second device. In this manner, the first device does not need to be continuously powered. The first device may, however, be maintained in a dormant state and then activated to an active state by the tool.
In yet another aspect of the present invention, the communication between the first and second devices may be by any of a variety of means. For example, electromagnetic waves, inductive coupling, pressure pulses, direct electrical contact, etc. may be used. The communication means may also be the means by which power is supplied to the first device.
In still another aspect of the present invention, communication between the devices may be used to control operation of the tool. For example, where the item of equipment is a valve and the tool is a shifting tool for displacing a closure member of the valve, communication between the first and second devices may be used to determine whether an excessive pressure differential exists across the closure member. This determination may then be utilized to control the displacement of the closure member by the tool. As another example, the tool may not be permitted to engage the item of equipment until the communication between the devices indicates that the tool is appropriately positioned relative to the item of equipment.
In yet another aspect of the present invention, communication between the devices may be used to monitor a status of the item of equipment. For example, the first device may be connected to a sensor, such as a pressure sensor, a strain gauge, a hardness sensor, a position sensor, etc., and may transmit data regarding the status to the second device.